Flare stack burner assembly



NOV. 10, 1970 ZlNK EIAL 3,539,285

FLARE STACK BURNER ASSEMBLY Filed March 20, 1969 2 Sheets-Sheet 1 3 52 3 5.2 23 52 52 52 42 5 53 5/ 2 I II W;

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ATTORNEY NOV. 10, 1970 N ETAL FLARE STACK BURNER ASSEMBLY 2 Sheets-Sheet 2 Filed March 20, 1969 IN VENTORS JOHN SMITH Z/NK ROBERT D. REED BY M A TTORNEY United States Patent 3,539,285 FLARE STACK BURNER ASSEMBLY John Smith Zink and Robert D. Reed, Tulsa, Okla., assignors to John Zink Company, Tulsa, Okla., a corporation of Delaware Filed Mar. 20, 1969, Ser. No. 808,880 Int. Cl. F23b /00; F23c 9/00 US. Cl. 431-202 2 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to a burner assembly for the combustion of gases at an elevated location and the invention more specifically pertains to structural elements in association with a flare stack to deliver steam and air throughout the waste gases at the upper end of the stack to insure mixing of the steam and air with virtually all portions of the dump gases in the combustion zone and to provide substantially smoke-free burning of the flared gases.

Steam has employed in the burning of waste or dump gases at the upper end of a flare stack in effort 'to promote smokeless combustion. A flare stack is usually of circular construction and it is an object of the present invention to provide nozzle structures for delivering a mixture of steam and air throughout the circular cross-section of the stack and at the upper end thereof and to deliver the steam and air mixture in quantities related to the quantity of flared gas moving upwardly in the various sectors of the stack.

Another object of the present invention is to provide nozzle structures which more fully utilizes the port energy of the streams of the smoke suppressant so that the mixture of steam and air penetrates the flared gas stream to thereby avoid the flared gas stream from overpowering the streams of smoke suppressant and to insure a more thorough mixing of the smoke suppressant with all portions of the flared gas.

Other objects and features of the invention will be appreciated and become apparent to those skilled in the art as the present disclosure proceeds and upon consideration of the following detailed description taken in conjunction With the accompanying drawings wherein an embodiment of the invention is disclosed.

In the drawings:

FIG. 1 is an elevational view of the upper end portion of a flare stack embodying the invention and with portions shown in section.

FIG. 2 is a plan view of the burner assembly.

FIG. 3 is a sectional view on a larger scale and taken on the line 3-3 of FIG. 1.

FIG. 4 is an enlarged fragmentary sectional view taken on the line 4-4 of FIG. 2.

FIG. 5 is a side elevational view of one of the nozzle structures for distributing a mixture of steam and air to the flared gas within the stack.

FIG. 6 is a transverse sectional view taken on the line 6-6 of FIG. 5.

FIG. 7 is an inverted plan view of the nozzle structure shown in FIG. 5 with a portion of the conduit line Patented Nov. 10, 1970 leading thereto shown in section and taken on the line 77 of FIG. 5.

The invention pertains to a flare stack equipped at its upper end with nozzle structures which provides for projection of a smoke suppressant throughout the flared gas and in the zone where combustion is to take place. In the embodiment shown in the drawing an upper portion of the flare stack is indicated at 10 having a generally cylindrical shape and a substantially circular opening 11 at the upper end thereof. The stack 10 may be fabricated to have any desired height so that the combustion of the dump gases adjacent the opening 11 takes place at the desired elevation above the surrounding terrain.

The manifold 12 may be mounted on the stack 10 beloW the upper end thereof into which steam is supplied. The steam is used as a smoke suppressant and also supplies energy for aspirating devices 15 which induce air to be mixed with the steam. A tube 14 guides steam from the manifold 12 for release through a port and for delivery into a conduit 16. The steam escaping from the port at the upper end of the tube 14 creates a low pressure condition and air is drawn into the conduit 16 for mixture with the steam. Such an aspirating assembly 15 is associated with each of the conduits which extend to the upper end portion of the stack. The conduit 16 extends through the wall of the stack 10 and upwardly along the axis thereof and terminates adjacent the upper end of the stack. The upper end of the conduit 16 is provided with a plurality of circumferentially spaced ports 22 as shown in FIG. 4 with their axes disposed in a substantially horizontal plane. A disc 23 overlies the upper end of the conduit and a plurality of circumferentially spaced lugs 24 maintain the disc 23 above the upper end of the conduit 16 so that open areas 26 are provided under the disc between the lugs 24. The lugs 24 may be welded to the disc 23 and to the conduit 16. The structure at the upper end of the conduit 16 provides a central discharge device and steam and air guided upwardly by the conduit 16 moves outward through the ports 22 and outwardly through the open areas 26.

A feature of the invention pertains to the structure of steam and air distributing devices 31 mounted within the stack 10 adjacent the upper end thereof. These steam and air distributing devices are designed for discharging the smoke suppressant throughout the larger diameter portion of the stack 10. The distributing devices 31 are of elongated shape and are disposed with their major dimensions in radial positions as will be apparent from a consideration of FIGS. 1 and 2. Each distributing device 31 has substantially parallel generally vertical side walls 32 as shown in FIGS. 5 and 6. End walls 34 close the areas between the side Walls 32 and abottom wall 33 closes the space between the end and side walls.

A conduit 36 associated with one of the aspirating devices 15 extends through the wall of the stack 10 and upwardly therin as shown in FIG. 1. The conduit 36 has an elliptical shaped upper end portion 37 where it is connected to one of the distributing devices 31. The flattened inverted conical shape portion 37 may be welded to the bottom wall 33 near the radially outer end thereof and a mixture of steam and air is thus delivered into the distributing device 31. An elongated plate 41 (FIGS. 5 and 6) is supported in spaced relationship above the upper edges of the side walls 32. The plate 41 extends from one end wall 34 to the other end wall. The plate 41 is maintained in position by a plurality of arched brackets 42 which are spaced from each other as best shown in FIG. 5. These brackets may be welded to the side walls 32 and to the plate 41 and they provide apertures 44 through which steam and air may escape. The end portions of the plate 41 may be supported by brackets 46.

There is a conduit 36 for each distributing device 31 and each conduit 36 supplies a mixture of steam and air at high velocity into the associated distributing device 31 near the outer end thereof and adjacent the wall of the stack 10. The steam and air impacts against the plate 41 and the greatest pressure developed in each distributing device 31 is in the zone directly above its conduit 36. Thus the steam and air escaping through the apertures 44 immediately above the conduit 36 provides that the greatest volume of the steam and air will be delivered into the dump gases adjacent the wall of the stack 10 and where the circumferential spacing of the outer end portions of 411 1 distributing devices is large. In proceeding radially inwardly of each distributing device 31 and towards the axis of the-.stack 10, there will be less steam and air delivered for mixture with a smaller volume of the dump gases moving upwardly between the distributing devices 31. The air and steam discharged through the apertures 44 is in directions which slope upwardly from a horizontal plane of the upper end of the stack 10. The volume of steam and air discharged into the flared gas is at a maximum near the wall of the stack 10 and lesser amounts are discharged in proceeding towards the axis of the stack 10 and the volume varies in general in proportion to the volume of the flared gas moving upwardly between the distributing device 31.

A plurality of vertically disposed pipes 51 receive steam and air from the =respective aspirating devices 15 associated with the manifold 12. The pipes 51 are disposed outside the stack 10 as shown in FIGS. 1 and 2. The upper ends of the pipes 51 are arranged between the conduits 36. A disc 52 closes the upper end of each pipe 51. The pipes 51 terminate above the distributing devices 31. Each pipe 51 has an opening 53 (FIG. 1) in the perimeter thereof and each opening 53 extends throughout about ninety degrees of the assocated pipe. The center line 55 (FIG. 3) of each opening 53 is disposed to release the steam and air from within each pipe 51 in a radially inward direction between each pair of distributing devices 31. In one embodiment the openings 53 each have an area of approximately three inches. The energy of the escaping smoke suppressant is spent at a distance of about sixty inches from the opening 53, and there is a projection of the steam and air in a generally horizontal direction from each pipe 51 for a distance of approximately fifteen inches. Such projection of the steam and air includes sufficient energy so that the upward movement of the flared gas will not overpower the streams of the smoke suppressant escaping through the openings 53 to provide thorough mixing of the steam and air with the flared gas.

The smoke suppressant is thus distributed throughout all of the dump gas moving upwardly through the stack 10 and the distributing devices 31 together with the conduit 16 and the pipes '51 to provide for a thorough mixing of the smoke suppressant with virtually all portions of the dump gases in the area of opening 11 at the upper end of the flare stack.

While the invention has been shown and described with reference to particular structural elements in association with a flare stack, it will be appreciated that changes may be made in the elements as well as the overall assembly. Such modifications and others may be made without departing from the spiritand scope of the invention as set forth in the appended claims.

What is claimed and desired to be secured by Letters Patent is:

1. In a flare stack burner, a generally vertical stack having an opening at the upper end through which gas may escape, a central discharge device within said opening substantially at the axis of the stack, means guiding a mixture of steam and air into said discharge device, said discharge device having ports for radially outward escape of the steam and air mixture, a plurality of elongated distributing devices arranged with their lengths in generally radial positions within said opening, said distributing devices having apertures spaced therealong, and means for guiding a mixture of steam and air into the outer end portion of each elongated distributing device whereby a larger volume of the mixture of steam and air escapes through the apertures adjacent outer end of each distributing device than the volume which escapes from the apertures near the inner end of each distributing device.

2. In a flare stack burner according to claim 1 including a plurality of pipes having upper end portions disposed outside said stack with each of said pipes arranged in a position between lines projectin'g radially outward from two adjacent elongated distributing devices, means for supplying a mixture of steam and air into each pipe, and each of said pipes having a discharge opening -for the escape of the steam and air mixture in a direction towards the axis of said stack.

References Cited UNITED STATES PATENTS 2,506,972 5/ 1950 Schellentrager 431202 3,273,627 9/1966 Fink et al. 43 l202 3,429,645 2/1969 Reed 431--202 EDWARD G. FAVORS, Primary Examiner US. Cl. X.R. 23-277 

